3com MSR 20-20 참조 매뉴얼

Use the undo dtmf time command to restore the default.

By default, the persisting time of sending DTMF and the interval for sending DTMF 
are both 120 milliseconds.

Note that the configuration will apply to the whole interface once you carry out 
the command.

# Set the persisting time of sending DTMF digits to 200 milliseconds, and the 
interval to 300 milliseconds.

<Sysname> system-view

[Sysname] voice-setup

[Sysname-voice] dtmf time persist 200

[Sysname-voice] dtmf time interval 300 

dtmf threshold analog index value1

undo dtmf threshold analog index

Analog FXS/FXO/E&M voice subscriber line view

analog: Analog voice subscriber line.

index: Index number corresponding to a threshold, an integer in the range of 0 to 
12.

value: Threshold corresponding to the specified index. The value range varies with 
indexes. For details, see Table 682.

According to the energy level of the row and column frequencies as well as the 
energy level of their double frequencies, the system determines whether the input 
DTMF digit is valid.

The maximum energy of the input signal in the row frequency group is ROWMAX 
and the corresponding double frequency energy is ROW2nd. The maximum 
energy in the column frequency group is COLMAX and the corresponding double 
frequency energy is COL2nd.

Table 682   Meaning of the index numbers

0 

The lower limit of (ROWMAX + 
COLMAX). The input signal which is 
otherwise regarded too weak is 
recognized as a DTMF digit when 
ROWMAX + COLMAX) > 0. 

1 to 4,999, with 
a default of 
1,400 

The larger the value is, 
the higher the detection 
reliability is. However, 
the sensitivity drops.